Inside knurling tool



United States Patent O 3,513,678 INSIDE KNURLING TOOL Klaus Meyer, 819 E. Market-St, Bloomington, Ill. 61701 Filed July 3, 1967, Ser. No. 650,749 Int. Cl. B25b 5/00 US. Cl. 72-208 6 Claims ABSTRACT OF THE DISCLOSURE An inside knurling tool for knurling surfaces of an opening, bore or the like. The tool has a pair of knurling rolls which are respectively supported for free rotary movement by a pair of mounting means which may be of identical construction and which support the pair of rolls for free rotary movement about their axes, respectively. A screw means is provided in order that the distance between the knurling rools can be adjusted.

BACKGROUND OF THE INVENTION The invention relates to knurling tools.

In particular, the invention relates to inside knurling tools.

There are, in the industrial arts, structures which require inside surfaces to be knurled. For example, if the opening of a given body does not have sufficient friction with a member which passes through this opening, it is possible, by knurling the surfaces of the opening, to increase the frictional engagement between the body and the member which passes through the opening thereof. The invention relates to a structure which is capable of providing such an inside knurl.

Although there are available at the present time many known tools for providing exterior knurls, considerable difficulties are encountered in providing inside knurls of the above type. When adapting a tool design for outside knurling to provide inside knurls, considerable difficulties are encountered both with the mounting and manipulation of the tool as well as in connection with the mounting and manipulation of the work. The reason for these difficulties reside not only in the fact that it is necessary to press the surface of the opening or the like and the knurling roll one against the other, but in addition it is necessary to displace the inside surface which is to be knurled and the knurling roll, one with respect to each other, so that the knurls will be distributed around the surface of the opening or the like. These requirements of pressing of the knurling roll against the surface which is to be knurled and displacement of the surface which is to "be knurled with respect to the knurling roll, while maintaining the pressure therebetween, create considerable dilficulties with known tools.

SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide an inside knurling tool which will avoid the above drawbacks.

In particular, it is an object of the present invention to provide an inside knurling tool which can be actuated in an extremely simple manner.

Furthermore, it is an object of the present invention to provide a structure of this type which can easily be adjusted so as to be able to knurl surfaces of openings of different diameters.

Also, it is an object of the invention to provide a construction which enables the location of the knurl along the axis of the opening to be adjusted.

In addition, it is an object of the invention to provide a construction which is of an exceedingly simple and rugged nature and which is very reliable in operation.

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Also, the objects of the invention include control of the depth of the knurl by proper setting of the adjustment, without requiring different knurling rolls; knurling in materials of different hardness, using the same knurling rolls for all, but adjusting radial pressure to compensate for hardness variations; maintain uniformly knurled surfaces when knurling rolls wear, by adjusting radial pressure for wear; and knurling rolls of different diameter, knurl configuration, face width to be used and interchanged in the same tool. Standard knurls, also used for external knurling can be utilized.

In accordance with the invention the knurling tool includes a pair of rotary knurling rolls and a pair of mounting means which respectively support the rolls for free rotary movement about their axes. A support means carries the pair of mounting means for situating the roll axes parallel to each other, and the pair of mounting means position the rolls so that they are at the same elevation when their axes extend vertically. The support means coacts with at least one of the mounting means to support it for movement toward and away from the other of the mounting means, and the support means carries an adjusting means for adjusting the distance between the pair of mounting means by moving at least this one mounting means toward and away from the other of the mounting means. In this way it is possible to place the pair of rolls inside an opening whose surface is to be knurled and to then actuate the adjusting means so as to press the pair of rolls against the surface which it is to be knurled at diametrically opposed parts of this surface. With this pressure thus provided between the pair of knurling rolls and the surface which is to be knurled, it is possible to rotate either the pair of rolls with respect to the surface or the body which has the surface which is to be knurled with respect to the rolls, and in this way the surface of the opening can be knurled all the way around its axis.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a side elevation of a knurling tool according to the invention;

FIG. 2 is a transverse section of the structure of FIG. 1 taken along line 22 of FIG. 1 in the direction of the arrows;

FIG. 3 is a longitudinal section of the structure of FIGS. 1 and 2 taken along line 33 of FIG. 2 in the direction of the arrows; and

FIG. 4 is a diagrammatic illustration of the manner in which the tool is used.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings, the inside knurling tool 10 illustrated therein includes a pair of identical rotary knurling rolls 12a and 12b. The pair of knurling rolls 12a and 12b are respectively supported for free rotary movement by a pair of mounting means 14a and 14b. The mounting means 14a includes a block 16a, which may be made of brass or the like and which is formed in its opposed side surfaces with a pair of parallel grooves 18a which extend perpendicularly to the axis of the roll 12a. In addition the block 16a of the mounting means 14a is formed with a threaded bore 20a which passes completely through the block 16a and which also extends perpendicularly with respect to the axis of the roll 12a. This block has a flat top surface and a flat bottom surface and is formed with a pair of threaded bores 22a extending upwardly in the block from its bottom surface. The left bore 22a shown in FIG. 3 has a bolt 24a threaded into it, and this bolt has its bottom head end freely supporting the roll 12a through which the bolt 24a passes so that in this way the roll 12a is Supported for free rotary movement. A spacer 26a is located between the roll 12a and the bottom surface of the block 16a.

The mounting means 14b is identical with the mounting means 14a except that its bores 20b is threaded oppositely to the threaded bore 20a.

A support means 30 is provided to support the pair of mounting means 14a and 14b for movement toward and away from each other, and the pair of mounting means because of their substantially identical construction situate the pair of rolls 12a and 12b at the same elevation when the parallel axes of these rolls extend vertically. The support means 30 includes a top wall 32 and a pair of opposed side walls 34. These side Walls 34 in turn have fixedly connected thereto a pair of elongated parallel guide ribs 36 which extend slidably into the grooves 18a of the block 16a and of course into the corresponding grooves of the block 16b. Countersunk screws 38, which have their heads countersunk into the bottom surfaces of the guide ribs 36 extend freely through bores of the side walls 34 and are received in threaded bores which extend upwardly into the top wall 32 from the bottom surface thereof, so that in this way the guide ribs 36 and side walls 34 are fixed to each other and are fixedly carried by the top wall 32. The support means 30 is completed by a pair of opposed end walls 40 fixed to the side walls 34 as by screws 42 (FIG. 1), and these end walls 40 extend downwardly to a distance which is slightly below the guide ribs 36.

An adjusting means is carried by the support means 30 to adjust the distance between the knurling rolls 12a and 12b, and this adjusting means includes a rotary screw 44 having oppositely threaded portions 46a and 46b respectively coacting with the oppositely threaded bores 20a and 20b, so that upon turning of the screw 44 of the adjusting means the pair of mounting means 14a and 14b will be simultaneously and equally displaced toward and away from each other, the oppositely directed threads of the screw 44 and of the bores 20a and 20b being identical insofar as their pitch is concerned. The pair of opposed end walls 40 are respectively formed with openings coaxial with the bores 20a and 20b and through which the ends of the screw 40 freely extend so that the screw 44 is freely turnable with respect to the end walls 40. At its right end, as viewed in FIGS. 1 and 3, the screw 44 fixedly carries a collar 48 while at its left end it fixedly carries a non-circular member such as the member 50 which has an exterior surface of hexagonal cross section. The member 50 as well as the collar 48 are fixed to the screw 44 as by any suitable set screws, cross pins, or the like, and these members 48 and 50 respectively have directed toward each other inner end faces which slidably engage the outer surfaces of the end walls 40, so that in this way while the screw 44 is free to rotate about its axis it cannot move axially with respect to the support means 30'.

A manually engageable means is carried by the support means 30 to facilitate manipulation thereof, and in the illustrated example the manually engageable means includes a pair of knobs 52 which are supported for free rotary movement on a pair of screws 54 which are respectively threaded into the top wall 32 from the top surface thereof. The knobs 52 are situated in the region of the end walls 40 respectively at equal distances therefrom, and the blocks 16a and 16b are also located at equal distances from the end walls 40.

Support means 30 can be further equipped with a means, such as a centrally located tapped hole 30a to rotatably connect the same support means with an external driving member, such as a spindle of a drill press, milling machine, lathe, etc., which, in turn, may be driven by a motor of manually. Tapped hole 30a or similarly useful attachment means may also serve to fix the position of the support means 30 in an operation where it appears advantageous to rotate the work piece.

It will be noted that the blocks 16a and 16b are respectively provided with the threaded bores 22a and 22b which extend upwardly from their bottom surfaces and a pair of these bores are provided for each block, these threaded bores 22a and 22b having their axes all situated in a common plane which extends perpendicularly to the top wall 32 and contains the axis of the screw 44, so that the threaded bores 22a and 22b do not extend upwardly beyond the screw 44. In this way there are a pair of inner threaded bores 22a and 22b which are shown in FIG. 3 respectively receiving the screws 24a and 24b which carry the rolls 12a and 12b, respectively, but if it is desired to initially situate these rolls further apart from each other, as when working with an opening of relatively large diameter, then it is possible to use the pair of outer threaded bores 22a and 22b. In addition, it is possible to replace the screws 24a and 24b with another pair of identical screws of different lengths and to use with these screws different spacers 26a and 26b of different lengths so that it is possible to control the distance at which the knurling rolls are located beneath the support means 30.

The manner in which the structure of the invention is used is shown schematically in FIG. 4 which diagrammatically illustrates the knurling rolls 12a and 12b with their axes 60a and 60b extending vertically. The rolls are shown in conjunction with a workpiece 62 in the form of a body of any metal or the like softer than the material of which the rolls 12a and 12b are made. The adjusting means formed by the screw 44 is initially turned so that the peripheries of the rolls 12a and 12b are located closer to each other than the diameter of the opening 64 which is formed in the body 62 and whose inner surface 66 is to be knurled. In this way, it is possible to introduce the knurling rolls into the interior of the opening 64 to be surrounded by the surface 66 which defines the opening 64. Then the screw 44 is turned so as to displace the knurling rolls apart from each other until they engage the surface 66, and a suitable wrench or the like is applied to the non-circular member 50 so as to tightly press the knurling rolls with a suitable pressure against the surface 66. With the parts in this position if the workpiece 62 is held in a suitable vise, for example, the operator may grasp both of the handles 52 and swing the tool about the axis of the opening 64 so that the surface 66 will be knurled along its entire circumference. However, it is also possible to fixedly mount the tool 10 in a suitable vise or the like and to rotate the workpiece with respect to the tool, depending upon the nature of the work.

The tool may also be operated by rotation transmitted from an external source rather than by movement of the handles.

It is therefore apparent that with the simple structure of the invention it is possible in an extremely convenient manner to provide a knurled surface for an opening or any other inner surface of a given workpiece.

What is claimed is:

1. An inside knurling tool comprising a plurality of knurling rolls, a plurality of mounting means respectively mounting said rolls for free rotary movement about their axes, respectively, support means carrying said plurality of mounting means for positioning said axes parallel to each other, said plurality of mounting means respectively situating said rolls at the same elevation when said parallel axes thereof extend vertically, and said support means supporting at least one of said mounting means and the roll carried thereby for movement toward and away from another of said mounting means and the roll carried by the latter, and adjusting means carried by said support means and co-acting with said one mounting means for moving the latter toward or away from the other of said mounting means to adjust the distance between said rolls, whereby said rolls can be placed in engagement with the surface of an opening to knurl the latter surface, at least said one mounting means including a block having a side surface formed with a groove extending perpendicularly to the axis of the knurling roll carried by said one mounting means, said support means having a guide rib extending into said groove for slidably guiding said block for movement toward and away from the other of said mounting means, said block being formed with a threaded bore passing therethrough perpendicularly to said axis of said knurling roll carried by said one mounting means, and said adjusting means including a rotary screw member carried by said support means for rotary movement and co-acting with said threaded bore of said block for dis placing the latter toward and away from the other mounting means.

2. The combination of claim 1 and wherein both of said mounting means include blocks formed with grooves extending perpendicularly to the parallel axes of said roll, and said guide rib extending into both of said grooves of said blocks, and both of said blocks being respectively formedwith coaxial threaded bores which are oppositely threaded, respectively, said screw having oppositely threaded portions respectively coacting with said oppositely threaded bores so that upon turning of said screw of said adjusting means both of said blocks are moved simultaneously toward or away from each other.

3. The combination of claim 2 and wherein said screw terminates at one end in a non-circular member adapted to be acted upon by a wrench or the like.

4. The combination of claim 3 and wherein said support means includes a top wall respectively slidably engaging top surfaces of said blocks, a pair of opposed side walls extending downwardly from said top wall and between which said blocks are located, said blocks being respectively provided with said grooves at opposed side surfaces of each of said blocks, and said side walls respectively carrying a pair of guide ribs respectively extending into said grooves at said opposed side surfaces of each block, said support means having a pair of opposed end walls through which ends of said screw respectively extend and said non-circular member of said screw being situated at the exterior of one of said end walls.

5. The combination of claim 4 and wherein said screw fixedly carries beyond and at the exterior of the other of said end walls a collar which prevents axial movement of said screw with respect to said support means.

6. The combination of claim 2 and wherein both of said mounting means includes a pair of mounting screws extending through said rolls and supporting the latter for free rotary movement and received in said blocks for connecting said rolls thereto.

References Cited UNITED STATES PATENTS Re. 24,714 10/1959 Bennett et a1 72703 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R. 72-211, 703 

